How to calculate my battery banks total Ah and KWh

Stan55

I have (24) flooded/sealed lead 2vdc 165ah batteries connected in series/parallel to 48vdc.

thats 4 strings of 12vdc.

the answer I got from an online calculator was 640ah=32.2 kw= 720 kwh.

Is this correct?

BB.

Welcome to the forum Stan,

If you have 24x 2 volt @165 AH cells... Those all would be put in series (adding voltage) for a 48 volt @ 165 AH battery bank...

If you had another string of 24 x volt @ 165 AH cells--Then connecting that second string in parallel with the first would give you a 48 volt @ 330 AH battery bank... (paralleling strings of cells--All the same voltage--will add to AH capacity).

I am not sure I understand your battery bank / cells / battery configuration. Do you have 2 volt cells, or 12 volt @ 165 AH cells... Say 24 of them (24x 12 volt @ 165 AH)...

That would give you a bank with 4x batteries in series (for 48 volt) and 6x parallel strings (6x 165 AH = ) 990 AH. And 4s*6p=24 total 12 volt batteries...

So--Things are not "tracking here"... To figure out the total bank storage in Watt*Hours (or kWH):

• 48 volts * 990 AH = 47,520 Watt*Hours = 47.52 kWH total storage capacity

For a "Typical" residential daily use FLA off grid system battery bank, roughly the daily usage (assuming 2 days of no-sun, and 50% maximum discharge for better battery bank life):

• 47,520 WH * 0.85 AC inverter eff * 1/2 days storage * 0.50 max planned discharge = 10,098 WH per day (or overnight) of draw suggested...

Anyway... That is the math... Need to confirm your batteries, how many, and there series/parallel configuration.

After we figure this out, can look at your next question about configuring your system for backup power....

-Bill